1. Field of the Invention
This invention relates to portable optical scanners for reading indicia of varying light reflectivity, and in particular to such scanners which are adapted to be worn on the person. The invention further relates to optical scanning systems in which the optical module for generating and emitting the light beam is physically separate and apart from the detector module.
2. Description of the Related Art
Various optical readers and optical scanning systems have been developed heretofore for reading indicia such as bar code symbols appearing on the label or on the surface of an article. The symbol itself is a coded pattern of indicia comprised of, for example, a series of bars of various widths spaced apart from one another to bound spaces of various widths, the bars and spaces having different light reflecting characteristics. The readers in scanning systems electro-optically transform the graphic indicia into electrical signals, which are decoded into alphanumeric characters that are intended to be descriptive of the article or some characteristic thereof. Such characteristics are typically represented in digital form and utilized as an input to a data processing system for applications in point-of-sale processing, inventory control and the like. Scanning systems of this general type have been disclosed, for example, in U.S. Pat. Nos. 4,251,798, 4,369,361, 4,387,297; and U.S. Pat. Nos. 4,409,470; 4,760,248; 4,896,026, all of which have been assigned to the present applicant. As disclosed in the above patents, one embodiment of such scanning systems includes, inter alia, a hand held, portable laser scanning device supported by a user, which is configured to allow the user to aim the scanning head of the device, and more particularly, a light beam, at a targeted symbol to be read.
Such prior art hand held devices generally incorporate a light-receiving module which receives the light that has been reflected from the bar code symbol and determines, from the reflected pattern, the sequences of bars and spaces within the symbol. The unit may also incorporate decoding circuitry to decode the received information and to recover the underlying data (for example the alphanumeric data) which the bar code symbol represents.
A "heads up" display unit comprising a head band and a bar code reader and visual display mounted thereon is disclosed in U.S. Pat. No. 5,208,449 for inventory management operations. The display allows cross-checking of commands issued orally by the operator into a microphone and speech recognition circuit and of codes read by the bar code reader.
It may in some circumstances be disadvantageous for the light generating and emitting module to be housed within the same unit as the light-receiving module and the decoding circuitry. In the first place, locating everything within the main housing requires that the bar code to be read is positioned so that most or at least a substantial proportion of the reflected light returns to the unit along the same path as the emitted light. It might not always be convenient for a user to position the bar code reading and/or the bar code so that the light is reflected back along the same path in that way. Secondly, locating everything within the same unit means that the unit has to be physically rather large and relatively heavy. Users may not find it easy to operate for long periods.
It is a general object of the present invention at least to alleviate some of these problems of the prior art.
It is a further object to provide a portable optical scanning system with improved ergonomics, and which will be easier for a user to operate for long periods.
It is a further object of the present invention to reduce the weight of a portable optical scanning system adapted to be held in the hand of a user, or mounted to the user's body.
Additional objects, advantages and novel features of the present invention will become apparent to those skilled in the art from this disclosure, including the following detailed description, as well as by practice of the invention. While the invention is described below with reference to preferred embodiments, it should be understood that the invention is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional applications, modifications and embodiments in other fields which are within the scope of the invention as disclosed and claimed herein and with respect to which the invention could be of significant utility.